Anna M. Calleja

Cardiac risk in patients aged >75 years with asymptomatic, severe aortic stenosis undergoing noncardiac surgery.

Severe aortic stenosis (AS) is a known predictor of cardiac risk during noncardiac surgery. However, for patients with asymptomatic AS, it is unclear whether aortic valve surgery should precede noncardiac surgery. We studied 30 patients with asymptomatic, severe AS with a mean age of 78 + or - 9 years, an aortic valve area of 0.77 + or - 0.16 cm(2), a mean gradient of 50.1 + or - 9.5 mm Hg, and a peak gradient of 84 + or - 22 mm Hg. They were compared to 60 age-matched (within 2 years) and gender-matched (ratio of 1:2) patients with mild-to-moderate AS (controls). The primary end point of the study was a composite of death, myocardial infarction, heart failure, ventricular arrhythmias before dismissal, and intraoperative hypotension requiring vasopressor administration. Most patients (>75%) and controls underwent intermediate-risk surgical procedures that were similar with respect to the nature of the surgery, type of anesthesia used, and preoperative risk assessment. Combined postoperative events were more common for the patients (n = 10; 33%) than for the controls (n = 14; 23%), but the difference was not statistically significant (p = 0.06). Intraoperative hypotension requiring vasopressor use was more likely for the patients (n = 9; 30%) than for the controls (n = 10; 17%; odds ratio 2.5; p = 0.11). The perioperative myocardial infarction rates were similar for both groups (3%; p = 0.74). No deaths, heart failure events, or ventricular arrhythmias occurred in the patients and 1 death and 1 ventricular arrhythmia episode occurred in the controls. In conclusion, intermediate-to-low-risk noncardiac surgery for patients with severe, asymptomatic AS can be performed relatively safely. Intraoperative hypotension was frequent and required prompt and aggressive treatment.

Impact of acute moderate elevation in left ventricular afterload on diastolic transmitral flow efficiency: analysis by vortex formation time.

BACKGROUND The formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. Vortex formation time (VFT) is an index of the optimal conditions for vortex formation. It was hypothesized that left ventricular (LV) afterload impairs diastolic transmitral flow efficiency and therefore shifts the VFT out of its optimal range. METHODS In 9 open-chest pigs, LV afterload was elevated by externally constricting the ascending aorta and increasing systolic blood pressure to 130% of baseline value for 3 minutes. RESULTS Systolic LV function decreased, diastolic filling velocity increased only during the late (atrial) phase from 0.46 +/- 0.06 to 0.63 +/- 0.19 m/s (P = .0231), and end-diastolic LV volume and heart rate remained unchanged. VFT decreased from 4.09 +/- 0.27 to 2.78 +/- 1.03 (P = .0046). CONCLUSION An acute, moderate elevation in LV afterload worsens conditions for diastolic vortex formation, suggesting impaired blood transport efficiency.

Revisiting the Simplified Bernoulli Equation

Background: The assessment of the severity of aortic valve stenosis is done by either invasive catheterization or non-invasive Doppler Echocardiography in conjunction with the simplified Bernoulli equation. The catheter measurement is generally considered more accurate, but the procedure is also more likely to have dangerous complications. Objective: The focus here is on examining computational fluid dynamics as an alternative method for analyzing the echo data and determining whether it can provide results similar to the catheter measurement. Methods: An in vitro heart model with a rigid orifice is used as a first step in comparing echocardiographic data, which uses the simplified Bernoulli equation, catheterization, and echocardiographic data, which uses computational fluid dynamics (i.e., the Navier-Stokes equations). Results: For a 0.93cm2 orifice, the maximum pressure gradient predicted by either the simplified Bernoulli equation or computational fluid dynamics was not significantly different from the experimental catheter measurement (p > 0.01). For a smaller 0.52cm2 orifice, there was a small but significant difference (p < 0.01) between the simplified Bernoulli equation and the computational fluid dynamics simulation, with the computational fluid dynamics simulation giving better agreement with experimental data for some turbulence models. Conclusion: For this simplified, in vitro system, the use of computational fluid dynamics provides an improvement over the simplified Bernoulli equation with the biggest improvement being seen at higher valvular stenosis levels.

Patients With Alzheimer Disease Have Altered Transmitral Flow Echocardiographic Analysis of the Vortex Formation Time

Objective. There is considerable epidemiologic evidence that Alzheimer disease (AD) is linked to cardiovascular risk factors and associated with an increased risk of symptomatic left ventricular (LV) dysfunction. Formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. The vortex formation time (VFT) is an index of optimal conditions for vortex formation. We hypothesized that AD and its associated cardiovascular risk factors impair diastolic transmitral flow efficiency and, therefore, shift the VFT value out of its optimal range. Methods. Echocardiographic studies were performed on 45 participants in total: 22 patients with AD diagnosed according to the American Psychiatric Associations criteria and 23 age‐matched individuals as a control group with cognitive function within normal limits. Results. The echocardiographic ratio of the early to atrial phases of the LV filling velocities was significantly lower in the AD group (mean ± SD, 0.67 ± 14) when compared with the control individuals (0.79 ± 0.14; P = .003). The interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, and right ventricular end‐diastolic diameter were significantly higher in the AD group (P ≤ 0.04). The mitral annular diameters in the control and AD groups were nearly identical (P = .725). The time‐velocity integral of the E wave had a lower value in the AD group than in the control group (P = .05), whereas the VFT was significantly lower in the AD group (P = .018). Conclusions. Our study suggests that patients with AD have impaired transmitral flow efficiency of diastolic filling, as measured by the VFT, compared with age‐matched control individuals.

Right ventricular free wall circumferential strain reflects graded elevation in acute right ventricular afterload

This study was designed to evaluate the concurrent changes in the right ventricular free wall (RVFW) movement in experimentally induced, acute mild, moderate, and severe right ventricle (RV) afterload conditions. In 14 open-chest pigs (weight 43 +/- 4 kg) with preserved pericardia, acute mild (>35 and <50 mmHg), moderate (> or =50 and < or =60 mmHg), and severe (>60 mmHg) increases in RV systolic pressure (RVSP) were induced by constriction of the pulmonary artery. At each step, longitudinal, radial, and circumferential strains and strain rates were measured in both the RVFW and the interventricular septum. The mean RVSPs were 31.0 +/- 4.3 mmHg at baseline and 41.1 +/- 2.7 mmHg during mild, 52.7 +/- 3.4 mmHg during moderate, and 61.7 +/- 1.6 mmHg during severe afterload conditions. The RVFW circumferential strains showed significant differences among baseline, mild, moderate, and severe afterload conditions (-10.5 +/- 3.9, -8.3 +/- 3.3, -5.4 +/- 2.7, and -7.5 +/- 5.3%, respectively, P = 0.008) and had significant linear correlation with RVSP (r = 0.636, P < 0.001) if the severe condition was excluded. Decrease of the RVFW circumferential strain magnitude is the most distinct response in acute mild and moderate RV afterload that could aid in detection of clinical conditions associated with acutely increasing RV afterload.

Selective echocardiographic analysis of epicardial and endocardial left ventricular rotational mechanics in an animal model of pericardial adhesions

AIMS Diagnosis of pericardial adhesions is challenging. Twisting of the left ventricle (LV) is essential for normal LV functioning. We experimentally characterized the impact of pericardial adhesions on epicardial and endocardial LV rotational mechanics with velocity vector imaging (VVI). METHODS AND RESULTS In nine open-chest pigs, the heart was exposed while preserving the pericardium. Early-stage pericardial adhesions were simulated by instilling tissue glue to pericardial space. Using VVI, LV rotational mechanics was quantitatively assessed endocardially and epicardially along with haemodynamic data at baseline and following the experimental intervention. End-diastolic volume, ejection fraction, stroke volume, late diastolic filling velocity, and LV endocardial torsion decreased significantly. LV epicardial torsion showed only a trend towards decrease (P = 0.141). Endocardial twist and torsion decreased significantly (P = 0.007) from 8.6 +/- 2.2 degree and 1.497 +/- 0.397 degree/cm to 5.3 +/- 1.8 degree and 0.97 +/- 0.38 degree/cm, respectively; epicardial twist showed a trend towards a decrease in its magnitude. Gradients of endocardial/epicardial twist and torsion did not significantly change. CONCLUSION The model suggests that early-stage pericardial adhesions reduce both epicardial and endocardial LV twist and torsion without a significant alteration in their transmural gradient. Selective endocardial/epicardial analysis of LV twisting mechanics may have a diagnostic role in detection of early formation of pericardial adhesions.

Multimodality imaging showing complete cardiovascular involvement by Erdheim-Chester disease.

Erdheim-Chester disease (ECD) is a multisystem non-Langerhans form of cell histiocytosis. Histiocytic infiltration leads to xanthogranulomatous infiltrates of multiple organ systems. Erdheim-Chester disease was first reported in 1930, only 320 cases reported in the literature. Cardiac involvement in ECD carries worst prognosis beside the central nervous system. We report the first case with pan-cardiac involvement diagnosed with multimodality imaging.

Impact of pericardial adhesions on diastolic function as assessed by vortex formation time, a parameter of transmitral flow efficiency

BackgroundPericardial adhesions are a pathophysiological marker of constrictive pericarditis (CP), which impairs cardiac filling by limiting the total cardiac volume compliance and diastolic filling function. We studied diastolic transmitral flow efficiency as a new parameter of filling function in a pericardial adhesion animal model. We hypothesized that vortex formation time (VFT), an index of optimal efficient diastolic transmitral flow, is altered by patchy pericardial-epicardial adhesions.MethodsIn 8 open-chest pigs, the heart was exposed while preserving the pericardium. We experimentally simulated early pericardial constriction and patchy adhesions by instilling instant glue into the pericardial space and using pericardial-epicardial stitches. We studied left ventricular (LV) function and characterized intraventricular blood flow with conventional and Doppler echocardiography at baseline and following the experimental intervention.ResultsSignificant decreases in end-diastolic volume, ejection fraction, stroke volume, and late diastolic filling velocity reflected the effects of the pericardial adhesions. The mean VFT value decreased from 3.61 ± 0.47 to 2.26 ± 0.45 (P = 0.0002). Hemodynamic variables indicated the inhibiting effect of pericardial adhesion on both contraction (decrease in systolic blood pressure and +dP/dt decreased) and relaxation (decrease in the magnitude of -dP/dt and prolongation of Tau) function.ConclusionPatchy pericardial adhesions not only negatively impact LV mechanical functioning but the decrease of VFT from normal to suboptimal value suggests impairment of transmitral flow efficiency.

Correlation of automated function imaging (AFI) to conventional strain analyses of regional and global right ventricular function.

BACKGROUND Automated function imaging is a software tool available to facilitate the efficiency of workflow when analyzing left ventricular strain. In this study, automated function imaging was compared with a conventional approach for the analysis of right ventricular strain in normal and pressure-overloaded right ventricles. METHODS Twelve pigs were subjected to graded acute right ventricular systolic pressure overload. Intraclass and interclass correlation coefficients (ICCs) with 95% confidence intervals were used for statistical evaluation, with grading based on the kappa statistic as follows: ICC >0.75 = excellent, 0.4 to 0.75 = good, and <0.40 = poor. RESULTS Intraobserver and interobserver variability for both regional and global strains consistently ranged from good to excellent (ICC, 0.50-0.99), with good agreement between the conventional and automated methods. CONCLUSION Automated function imaging correlates well with conventional strain analysis of the right ventricle. Automated function imaging is a practical tool for measuring regional and global longitudinal strain in both normal and pressure-overloaded right ventricles.

Quantification of Left Ventricular Twisting Mechanics by Velocity Vector Imaging in an Animal Model of Pericardial Adhesions

Diagnosis of constrictive pericarditis remains clinically challenging. Untwisting of the left ventricle (LV) is essential for normal LV diastolic function. Echocardiography is able to measure LV twisting mechanics. We designed an animal model of constrictive pericarditis to determine how pericardial-epicardial adhesions impair LV twisting mechanics. In eight open-chest pigs, the heart was exposed while preserving the pericardium. We simulated early constrictive pericarditis by pericardial constriction and patchy adhesions induced with instant glue and pericardial-epicardial stitches. Using Velocity Vector Imaging (VVI), LV magnitudes of twisting and untwisting were measured along with hemodynamic data at baseline and after the experimental intervention. Significant decreases in end-diastolic volume, ejection fraction, stroke volume, and late diastolic filling velocity reflected the effects of the pericardial adhesions. Magnitude of LV untwisting rate decreased from -80+/-23 degrees /s to -26+/-10 degrees /s (p=0.0009). LV twisting rate dropped from 78+/-20 degrees /s to 40+/-8 degrees /s (p=0.0039) and LV twist magnitude decreased from 9+/-2 degrees to 5+/-2 degrees (p=0.0081). Patchy pericardial adhesions are associated with reductions in LV untwisting rate and twisting magnitude, consistent with a negative impact of constrictive pericarditis on systolic and diastolic function. Impairments in LV twisting mechanics may have a diagnostic role in the detection of early stages of constrictive pericarditis.